Oscillator



April 1939- H. E. HOLLMANN 2,153,190

OSCILLATOR Filed April 14, 1937 INVENTOR HANS E. HOLLMANN W ATTORNEYPatented Apr. 4, 1939 imirso STATES PATENT OFFICE OSCILLATOR tion ofGermany Application April 14, 1937, Serial No. 136,744 In Germany April8, 1936 14 Claims.

This invention relates to oscillators, and in particular to electrondischarge type oscillators, wherein displacement currents produced by abeam of electrons is utilized.

The invention described in the following rep- -resents the furtherdevelopment of the arrangement described in my copending applicationentitled Electronic system, filed February 24, 1937, and bearing SerialNo. 127,343, and relates to an arrangement for the production ofultra-short wave oscillations in accordance with the principle oflateral control. The arrangement is such that a filament-like or flatelectron ray is transversely deflected by an electrical cross field, andat the 15 same time formed into a closed curve such as a circular curvefor instance, so that it intersects its own course. In this way it isaccomplished that the ray passes a second time through the controllingfield thereby delivering to said field 20 its energy of oscillation.Thus only a single lateral field is present which takes care at the sametime of the deviation of the ray and the decoupling of its energy.Through proper matching of the electron travel times in the ray it canbe achieved that the building up resistance between the cross fieldplates becomes negative at corresponding frequencies, so that aresonance system connected to the plates can be caused to oscillate.

30 The arrangement for producing electrical oscillations and moreespecially ultra-short wave oscillations described in the aboveidentified coending application, operates with a transversal control ofan electron ray through an electrical 35, cross field in contrast to thehitherto customary control of the longitudinal density of an electroncurrent. The characteristic feature of the above identified applicationdoes not reside in this cross field control as such, but in the factthat the electron ray instead of delivering its energy through impingingon anode plates, passes after leaving the controlling deflection field,through a second lateral field to which it delivers its energy ofoscillation contained in its transversal space 45 charge movement,through influence action. When operating with very high frequencies theadvantage is hereby obtained that space charge congestions appearing atthe transit of the ray which carries out a very rapid to and fro move.-

ovment, to one or several plates, and which more and more flatten outthe building up characteristics, do not any longer play an importantpart.

In fact, the steepness of the dynamical working characteristicscontinuously increases with an in- 5s crease in frequency, since theinduced component of the displacement current is a direct function ofthe velocity amplitude of the space charge oscillating between thecollector plates. The travel times which the electrons require for themovement from the control field to the absorption field cannot be chosenfreely in view of a sufiiciently high geometrical sensitivity of thedeflection and amplitude increase, and therefore, they must be so chosenin accordance with the feed back conditions of the circuit, that thephase angle between the control potential and the influence outputcurrents is a whole number multiple of 180.

In the arrangement according to the above identified copendingapplication, the plates of the two lateral fields through which the raypasses in succession, have each a resonance circuit connected thereto,and the building up of the oscillations depends on the phase correctfeed back which may be an inductive feed back or 2 direct feed back,whereby in the simplest case, the two oscillatory systems have the formof a pair of parallel wires connecting both pairs of plates in the samesense or in a crosswise fashion.

The push-pull arrangement described in my copending application aboveidentified, avoids a special circuit type or external feed back. In thisarrangement in place of the external feed back channel a second electronray is provided whose direction is opposite to that of the first ray,and which likewise permeates the two lateral fields but in reversedsequence. In this pushpull arrangement the circular course of the feedback is so closed between the two lateral fields that each lateral fieldserves at the same time as control field and decoupling field.

This idea, namely to save a special feed back channel and to place thefeed back instead exclusively into the electron rays, is now applied toa single electron ray in accordance with the present invention. To thisend, an electron ray after leaving the control field is so bent into acircular course through any type of fields such as electron opticalsystems, magnetic or electrostatic lens systems or prismatic systems, orthrough a constant homogeneous magnetic field transversal to thedirection of the ray, that it passes a second time through the controlfield before it is absorbed by an absorption electrode.

An arrangement embodying the idea of the invention is shown as anexample of construction schematically in the figure. Herein item K isthe cathode whose electrons after concentration by means of a lenssystem L pass through the anode A1 in the form of a sharp beam of rayshaving a round or rectangular cross section. Items P1 and P2 representthe two deflection plates forming together with the inductive loop B anoscillatory circuit having a very high natural frequency. By means of amagnetic field H directed perpendicularly to the drawing plane andindicated by the circle embracing the crosses, the ray after leaving thespace between the plates is deflected into a circular course so that itpasses for the second time through the lateral field Pl, P2 thereafterimpinging on the anode A2. Iron sheets E forming a magnetic shieldprevent the ray from being already deflected ahead of its first entranceinto the lateral field, and likewise after its second exit, as a resultof which the electron course shown is obtainable. If the ray isdeflected out of position of rest through a potential differenceappearing between P1 and P2, then also the returning ray is subjected toa greater deflection in, a corresponding manner, and delivers its energythrough influence action to the resonance circuit P1, P2, B. If theelectron travel time along the circular course is brought into adefinite relationship to the natural frequency of the circuit P1, P2,13, namely such that the influencing resonance potentials just act inopposition to the original deflection potentials, a regenerativeperformance takes place, and the oscillatory circuit P1, P2, B will beexcited. Since the entire building-up mechanism, i. e. the energyfeedback as well as the external or circuit type feed back is displacedinto the electron ray, it can be said: The dynamical electron resistancebetween the two lateral plates P1 and P2 becomes negative at therespective frequency for the properly matched arrangement.

Next it is assumed for the sake of simplicity, that the electron passonly once through the circular path shown in the figure. This assumptionneed not necessarily be made, and the case may obviously occur that alarge number of electrons prescribe this course several times, andtherefore, contribute several times to the delivery of energy beforereaching the anode A2 in the tangential direction. This will beparticularly the case if the absorption electrode A2 is inserted in thepath of the ray in the form of a ray stop.

The invention is susceptible of numerous modifications without departingfrom the principle of the idea of the invention. The lateral fieldbetween the plates P1 and P2 may for instance be divided into severalpartial fields connected alternately in opposite phase soas to renderits length independent of the time of passage of the electrons such ashas already been proposed in oscillograph tubes at extremely highfrequencies for increasing the sensitivity. At any rate it is seen thatthe new arrangement is capable of supplying undamped short waveoscillations at sufficient ray amperage, such as are not obtainable withthe hitherto known arrangement.

Having described my invention, what I claim 1 The method of producingoscillations comprising the steps of producing a beam of electrons,directing the produced beam along a predetermined path, producingdisplacement currents from the directed beam of electrons, producingoscillatory energy from the produced displacement currents subsequentlydirecting the beam of electrons to cross the predetermined path, andaugmenting theproduced oscillatory energy at the point of crossing thepredetermined path by the directed beam of electrons.

2. An electronic oscillator comprising an envelope, electron beamproducing means positioned Within the envelope, a target electrodepositioned in angular relation to the beam producing means, and anoscillatory circuit having opposed plates positioned at an angle to theaxis .of the beam producing means and intermediate the beam producingmeans and the target electrode.

3. An electronic oscillator comprising an envelope, electron beamproducing means positioned within the envelope, a target electrodepositioned in angular relation to the beam producing means, anoscillatory circuit having opposed plates positioned at an angle to theaxis of the beam producing means and intermediate the beam producingmeans and the target electrode, an electromagnetic field displacedlaterally from the oscillatory circuit, and electromagnetic shieldmembers positioned to shield the oscillatory circuit.

4. The method of producing oscillations comprising the steps ofproducing a beam of elec trons, directing the produced beam along apredetermined path, producing displacement currents from the directedbeam of electrons, producing oscillatory energy from the produceddisplacement currents, subsequently directing the beam of electrons tocross the predetermined path, producing further displacement currents bythe directed beam of electrons in the region at which the beam crosses apredetermined path, and producing oscillatory energy in phase with thefirst named oscillatory energy by the said further displacementcurrents.

5 The method of producing oscillations comprising the steps of producinga beam of electrons, directing the produced beam along a predeterminedpath, producing displacement currents from the directed beam ofelectrons, producing oscillatory energy from the produced displacementcurrents, subsequently directing the beam of electrons to cross thepredetermined path, producing further displacement currents by thedirected beam of electrons in the region at which the beam crosses apredetedmined path, producing oscillatory energy in phase with the firstnamed oscillatory energy by the said further displacement currents, andsubsequently collecting the electrons of the directed beam.

6. The method of producing oscillations comprising the steps ofproducing a beam of electrons, directing the produced beam along apredetermined path, producing displacement currents from the directedbeam of electrons, producing oscillatory energy from the produceddisplacement currents, subsequently electromagnetically directing thebeam of electrons to cross the predetermined path, producing furtherdisplacement currents by the directed beam of electrons in the region atwhich the beam crosses a predetermined path, and producing oscillatoryenergy in phase with the first named oscillatory energy by the saidfurther displacement currents.

7. The method of producing oscillations comprising the steps ofproducing a beam of electrons, directing the produced beam along apredetermined path, producing displacement currents from the directedbeam of electrons, producing oscillatory energy from the produceddisplacement currents, subsequently electromagnetically directing thebeam of electrons to cross the predetermined path, producing furtherdisplacement currents by the directed beam of electrons in the region atwhich the beam crosses a predetermined path, producing oscillatoryenergy in phase with the first named oscillatory energy by the saidfurther displacement currents, and

subsequently collecting the electrons of the directed beam.

8. An electronic oscillator comprising means for producing a beam ofelectrons, means for directing the produced beam along a predeterminedpath, means for producing displacement currents from the directed beamof electrons, means for producing oscillatory energy from the produceddisplacement currents, means for subsequently directing the beam ofelectrons to cross the predetermined path, means for producing furtherdisplacement currents by the directed beam of electrons in the region atwhich the beam crosses a predetermined path, and means for producingoscillatory energy in phase with the first named oscillatory energy bythe said further displacement currents.

9. An electronic oscillator comprising means for producing a beam ofelectrons, means for directing the produced beam along a predeterminedpath, means for producing displacement currents from the directed beamof electrons, means for producing oscillatory energy from the produceddisplacement currents, means for subsequently directing the beam ofelectrons to cross the predetermined path, means for producing furtherdisplacement currents by the directed beam of electrons in the region atwhich the beam crosses a predetermined path, means for producingoscillatory energy in phase with the first named oscillatory energy bythe said further displacement currents, and means for subsequentlycollecting the electrons of the directed beam.

10. An electronic oscillator comprising means for producing a beam ofelectrons, means for directing the produced beam along a predeterminedpath, means for producing displacement currents from the directed beamof electrons, means for producing oscillatory energy from the produceddisplacement currents, means for subsequently electromagneticallydirecting the beam of electrons to cross the predetermined path, meansfor producing further displacement currents by the directed beam ofelectrons in the region at which the beam crosses a predetermined path,and means for producing oscillatory energy in phase with the first namedoscillatory energy by the said further displacement currents.

11. An electronic oscillator comprising means for producing a beam ofelectrons, means for directing the produced beam along a predeterminedpath, means for producing displacement currents from the directed beamof electrons, means for producing oscillatory energy from the produceddisplacement currents, means for subsequently electromagneticallydirecting the beam of electrons to cross the predetermined path, meansfor producing further displacement currents by the directed beam ofelectrons in the region at which the beam crosses a predetermined path,means for producing oscillatory energy in phase with the first namedoscillatory energy by the said further displacement currents, and meansfor subsequently collecting the electrons of the directed beam.

12. The method of producing oscillations comprising the steps ofproducing a beam of electrons, directing the produced beam along a predetermined path, producing displacement currents from the directed beamof electrons, producing oscillatory energy from the produceddisplacement currents, subsequently electromagnetically directing thebeam of electrons to cross the predetermined path, and augmenting theproduced oscillatory energy at the point of crossing the path by thedirected beam of electrons.

13. An electronic oscillator comprising means for producing a beam ofelectrons, means for directing the produced beam along a predeterminedpath, means for producing displacement currents from the directed beamof electrons, means for producing oscillatory energy from the produceddisplacement currents, means for subsequently directing the beam ofelectrons to cross the predetermined path whereby the oscillatory energyis augmented at the point of cross-over by the subsequently directedbeam of electrons.

14. An electronic oscillator comprising means for producing a beam ofelectrons, means for directing the produced beam along a predeterminedpath, means for producing displacement currents from the directed beamof electrons, means for producing oscillatory energy from the produceddisplacement currents, means for subsequently electromagneticallydirecting the beam of electrons to cross the predetermined path wherebythe oscillatory energy is augmented at the point of cross-over by thesubsequently directed beam of electrons.

HANS E. HOLLMANN.

